Understanding Domain Names, Email Accounts And Email Addresses

emailMany people that are new to email seem to have difficulty understanding the difference between:

  • Email domains
  • Email accounts
  • Email mailboxes
  • Email addresses.

Let’s start by looking at a typical email address:


Here is a quick Diagram that shows how they are related.


The Email Address can be split into two components

The part before the @ is the mailbox name and the part following the @ is the domain name.

The mailbox name links to physical storage on the email server to the email address.

Normally there is a 1 to 1 relationship between the mailbox name and the storage. However, because it is linked then multiple email addresses can be linked to the same physical mailbox.

An email account is a username and password combination that gives you access to a mailbox where your email is stored.

Domain Names

Personal email addresses using Yahoo, Gmail etc use the Gmail or Yahoo domain name.

Business email should use their own domain name and this domain name can also be used for the website address.

Domain names are not case sensitive.

Mailbox names

Although mailbox names are strictly speaking case sensitive most email providers don’t implement this rule so although the mailbox names Steve and steve should be different they normally aren’t.

So email sent to either [email protected] or [email protected] would be delivered to the same mailbox.

Email Addresses -Mailbox Naming Guidelines

Although special character including spaces are allowed in mailbox names it is recommend that you restrict your names to:

  • Alphanumeric characters (a-z,0-9).
  • The dot .
  • Hyphen
  • underscore

Although many so called special characters are allowed, but some can cause problems.

The most common special character is the . (dot). I would recommend that you don’t use any other special characters.

The Wiki has a list of valid characters taken for RFC 5321

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